The deal is pending completion of a physical exam, Garber said.
Miller, 32, posted a 45-25 record from 2001 through 2003 in Houston, but his career since has been devastated by injuries.
While Jays officials acknowledged that they've watched Miller work out and told him they're willing to bring him to camp on a minor league contract, general manager J.P. Ricciardi said more steps would have to be taken before a deal is in place.
"We have not talked anything in regards to contract yet,'' Ricciardi said.
Wade failed in comeback attempts with Boston and the Chicago Cubs, and has pitched only 35 2/3 innings in the major leagues since 2005.
Garber said that Miller "feels great'' after taking a year off, and chose Toronto over two other undisclosed suitors.
Toronto's starters led the majors with a 3.72 ERA last season, but the Blue Jays' rotation has taken a major hit with injuries to Shaun Marcum and Dustin McGowan and the departure of A.J. Burnett to the Yankees through free agency.
Jesse Litsch, Scott Richmond, David Purcey, Matt Clement, Mike Maroth, Casey Janssen and Brett Cecil are among the pitchers competing for rotation spots behind staff ace Roy Halladay in spring training.
Jerry Crasnick covers baseball for ESPN.com.